A tricuspid valve (TV) is an atrioventricular valve located in the right side of the human heart, between the right atrium (RA) and the right ventricle (RV). Anatomy of the TV is constituted of three asymmetrical leaflets, septal, anterior, and posterior, supported by a complex sub-valvular apparatus constituted by the chordae tendineae and the papillary muscles. The TV is also in proximity of the tendon of Todaro, where the heart's delicate atrioventricular node is located.
Regurgitant flow occurs during the systolic phases of the cardiac cycle when the tricuspid valve becomes incompetent. The incompetence is mainly caused by the pathology-induced progressive enlargement of the valve's annulus, which prevents the leaflets from reaching full coaptation during systole (or during the systole phase of the cardiac cycle). The lack of leaflets coaptation causes the development of a regurgitant orifice within the valve through which blood can reenter the right atrium instead of exiting the right ventricle via the pulmonary valve. This condition induces a cardiac overload with subsequent enlargement of the right ventricle and the right atrium, reduction of the right ventricular stroke volume, and increase in systemic vein congestion and other symptoms of congestive heart failure. Tricuspid valve regurgitation can be isolated from or associated to other valvulopathies, and leads to congestive heart failure, with reduced functional cardiovascular capacity and ultimately increased risks of mortality.
Surgical repair or replacement are the most commonly used techniques for treating this pathology, but the clinical results (e.g. mortality and recurrence) are suboptimal. Also, due to the common presence of several comorbidities in most patients affected by tricuspid regurgitation, the majority is ineligible for surgical repair or replacement because of the high risk correlated with those procedures.
Transcatheter therapy doesn't require open-heart surgery and could be a viable safer alternative. The unique anatomical feature of the tricuspid valve is the main challenge for developing a safe and effective implant. The anchoring possibly requires burdening of the adjacent cardiac structure (e.g. superior or inferior vena cava, the atrioventricular node, the coronary sinus, the right coronary artery, the ventricular myocardium). Also, the low pressure and output of the hemodynamic flow in the right side of the heart increases the risks of inducing atrioventricular pressure gradient and thrombogenesis.
It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.